The present invention is directed to supplemental spine fixation devices and methods which are used as an adjunct to a primary spine fusion method and/or device, such as by way of example only, an inter-body fusion device. The present invention is also directed to a method and apparatus for engaging adjacent spinous processes without the use of a primary spinal fusion method or device.
A common procedure for handling pain associated with degenerative spinal disk disease is the use of devices for fusing together two or more adjacent vertebral bodies. The procedure is known by a number of terms, one of which is inter-body fusion. Inter-body fusion can be accomplished through the use of a number of devices and methods known in the art. These include screw arrangements, solid bone implant methodologies, and fusion devices which include a cage or other mechanism which is packed with bone and/or bone growth inducing substances. All of the above are implanted between adjacent vertebral bodies in order to fuse the vertebral bodies together, alleviating associated pain.
Associated with such primary fusion devices and methods are supplemental devices which assist in the fusion process. These supplemental devices assist during the several month period when bone from the adjacent vertebral bodies is growing together through the primary fusion device in order to fuse the adjacent vertebral bodies. During this period it is advantageous to have the vertebral bodies held immobile with respect to each other so sufficient bone growth can be established.
Such supplemental devices can include hook and rod arrangements, screw arrangements and a number of other devices which include straps, wires, and bands, all of which are used to immobilize one portion of the spine relative to another. All of these devices generally require extensive surgical procedures in addition to the extensive procedure surrounding the primary fusion implant.
It would be advantageous if the device and procedure for supplemental spine fixation were as simple and easy to perform as possible, and were designed to leave intact as much bone, ligament, and other tissue which comprise and surround the spine, as possible.
The present invention is directed to providing a supplemental spine fixation device and method for alleviating discomfort associated with the spine and as an adjunct, if desired, to a primary spine fusion technique.
The present invention provides for a method and apparatus for assisting in the fusing together of vertebral bodies of the spine. One of the features and purposes of the invention is to immobilize the vertebral bodies while spine fusion is accomplished. Fusion can require upwards of six months for bone cells from the upper and lower vertebral bodies to grow towards each other, generally through a primary fusion device.
In order to assist in the fusing process, the supplemental spinal fixation device and method of the invention immobilizes the vertebral bodies by immobilizing the respective spinous processes extending therefrom. The present device and method of the invention is minimally invasive such that it does not add to the trauma of the primary fusion procedure, especially if the fusion procedure is from a posterior approach. With an anterior fusion approach, additional posterior incisions are required. However, these are minimal when compared to other devices and methods.
It is also to be understood that the apparatus and method of the present invention can be used without spinal fusion in order to immobilize the spinous processes.
Accordingly, an object of the present invention is to increase the rigidity and stability with respect to the adjacent spinous process and vertebral bodies in order to promote inter-body fusion between the vertebral bodies. A further object is to provide for such rigidity and stability without interbody fusion. For example the embodiment of the present invention can be used with an inventive spinous process distraction mechanism.
It is yet a further object of the present invention to provide for an implant and method which does not require modification of the bone, ligaments, or adjoining tissues. In other words, it is an object of the present invention to provide for an implant and method which does not require that the bone be reshaped, notched, or in anyway modified. It is also an object that there is as little modification as possible to soft tissue and ligaments surrounding the bone.
It is a further object of the present invention to provide for an implant and method which can be inserted from one side of adjacent spinous processes in order to immobilize the spinous processes and resultingly immobilize the adjacent vertebral bodies. By addressing the spinous processes from one side, the objects and advantages of a minimally invasive procedure with reduced trauma, can be accomplished.
It is yet a further object of the present invention to provide for a device which has securing and/or hook elements which can easily and conveniently be secured about the spinous processes, which hook devices are preferably designed in order to accommodate the shape of the spinous processes and preferably swivel or pivot in order to accommodate the position and shape of one spinous processes relative to another.
It is yet another object of the present of the invention to provide for a device which has several degrees of freedom in order to allow a portion of the device to be positioned between spinous processes in order to distract part the spinous processes and other portions of the device to engage the spinous processes in order to rigidly immobilize the spinous processes. These degrees of freedom allow the device to conform to the bones, ligaments, and tissues of each individual patient. Thus, the present device allows for adjustments along two and three axis in order to successfully immobilize spinous processes.
It is yet another object of the invention to provide a device and method for securing together adjacent spinous processes which device is rigid and can keep the spinous processes aligned.
Other aspects, objects and advantages of the invention are evident from the specification, the claims and the figures.